A known device that absorbs such type of pulsation includes a diaphragm damper device located in, for example, a fluid passage of a high-pressure fuel pump (hereinafter referred to as “prior art.” Refer to, for example, patent document 1). In the prior art, a damper device arranged in a fluid passage of a high-pressure fuel pump absorbs pressure pulsation of fuel discharged from the high-pressure fuel pump and reduces the pulsation width of the fuel pressure to stabilize the injection amount of the fuel.
In the diaphragm damper device of the prior art, in order to increase the effect for reducing the fuel pressure pulsation, as shown in FIG. 7, two diaphragm dampers 51 and 55 are arranged in the vertical direction. Diaphragms 52 and 53 of the first diaphragm damper 51 are held between a first support 61 and a third support 63, and diaphragms 56 and 57 of the second diaphragm damper 55 are held between a second support 62 and the third support 63.
The diaphragms 52 and 53 of the first diaphragm damper 51, the first support 61, and the third support 63 are welded and integrally fixed together at outer circumferential ends of the first diaphragm damper 51. In the same manner, the diaphragms 56 and 57 of the second diaphragm damper 55, the second support 62, and the third support 63 are welded and integrally fixed together at outer circumferential ends of the second diaphragm damper 55.
When setting a plurality of diaphragm dampers, the diaphragm dampers need to be integrated in order to increase the coupling efficiency. For example, when manufacturing a diaphragm damper device 50 including the plurality of diaphragm dampers 51 and 55 like in the prior art shown in FIG. 7, the enclosing of gas into the two diaphragm dampers 51 and 55 and the welding of the outer circumferential ends are simultaneously performed in a pressure container in which a gas mixture including helium is enclosed. More specifically, in a state in which there is a gap between the diaphragms 52 and 53 of the first diaphragm damper 51 and between the diaphragms 56 and 57 of the second diaphragm damper 55, high-pressure gas is drawn into the inside (gaps) of the diaphragms. In a state in which the diaphragm 53 of the first diaphragm damper 51 and the diaphragm 56 of the second diaphragm damper 55 are held by the third support 63, the diaphragm 52 of the first diaphragm damper 51 is upwardly moved with the first support 61 to contact the corresponding diaphragm, and the diaphragm 57 of the second diaphragm damper 55 is downwardly moved with the second support 62 to contact the corresponding diaphragm. The outer circumferential end surfaces of the two diaphragm dampers 51 and 55 are irradiated with a laser beam to entirely weld the outer circumferences of the diaphragm dampers 51 and 55 while rotating the pair of diaphragms 52 and 53 and the pair of diaphragms 56 and 57 in a state in which the diaphragms 52 and 53 are in contact with each other and the diaphragms 56 and 57 are in contact with each other.
In this manner, in the damper device of the prior art, the drawing of gas and welding need to be performed while simultaneously holding and moving all of the diaphragms of the two diaphragm dampers 51 and 55. Thus, the manufacturing device is complicated and large. Such a situation becomes prominent when increasing the number of diaphragm dampers to increase the effect for reducing fuel pressure pulsation.